CVE-2025-41703
📋 TL;DR
An unauthenticated remote attacker can send a Modbus command to turn off the output of an Uninterruptible Power Supply (UPS), causing a denial of service. This affects UPS devices that expose Modbus interfaces without proper authentication controls. Organizations using vulnerable UPS systems for critical infrastructure are at risk.
💻 Affected Systems
- Specific UPS models not listed in references; likely various UPS devices with Modbus interfaces
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Critical infrastructure loses power unexpectedly, causing equipment damage, data loss, or safety hazards in industrial/medical environments.
Likely Case
UPS shuts down, causing temporary power loss to connected equipment until manually restarted.
If Mitigated
Attack fails due to network segmentation, authentication requirements, or disabled Modbus interface.
🎯 Exploit Status
Simple Modbus command execution; no authentication required. Attack tools for Modbus are widely available.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: Not provided in references
Restart Required: No
Instructions:
1. Contact UPS vendor for firmware updates. 2. Apply vendor-provided patches if available. 3. Verify Modbus interface configuration after update.
🔧 Temporary Workarounds
Disable Modbus TCP/IP interface
allTurn off Modbus network interface if not required for operations
Vendor-specific configuration commands; consult device manual
Implement network access controls
allRestrict access to UPS Modbus port (typically TCP 502) using firewalls
iptables -A INPUT -p tcp --dport 502 -j DROP (Linux)
netsh advfirewall firewall add rule name="Block UPS Modbus" dir=in action=block protocol=TCP localport=502 (Windows)
🧯 If You Can't Patch
- Segment UPS devices on isolated network VLAN with strict firewall rules
- Implement physical security controls to prevent unauthorized access to UPS management interfaces
🔍 How to Verify
Check if Vulnerable:
Test if Modbus TCP port 502 is accessible and accepts unauthenticated commands to control UPS outputCheck Version:
Vendor-specific command via serial console or web interface; typically not standard across devicesVerify Fix Applied:
Verify Modbus interface is disabled or requires authentication; test that shutdown commands are rejected📡 Detection & Monitoring
Log Indicators:
- Modbus command logs showing unauthorized shutdown attempts
- UPS event logs indicating unexpected output disable
Network Indicators:
- Unusual Modbus traffic to UPS devices, especially from untrusted sources
- TCP port 502 connections from unexpected IP addresses
SIEM Query:
source_ip OUTSIDE trusted_networks AND dest_port=502 AND protocol="Modbus" AND (function_code=5 OR function_code=6)